[Gluster-users] Gluster 3.5.2 gluster, how does cache work?

[Juan José Pavlik Salles]

Hi guys, I've been reading a bit about caching in gluster volumes, but I
still don't get a few things. I set up a gluster replica 2 volume like this:

[root at gluster-test-1 ~]# gluster vol info vol_rep
Volume Name: vol_rep
Type: Replicate
Volume ID: b77db06d-2686-46c7-951f-e43bde21d8ec
Status: Started
Number of Bricks: 1 x 2 = 2
Transport-type: tcp
Bricks:
Brick1: gluster-test-1:/ladrillos/l1/l
Brick2: gluster-test-2:/ladrillos/l1/l
Options Reconfigured:
performance.cache-min-file-size: 90MB
performance.cache-max-file-size: 256MB
performance.cache-refresh-timeout: 60
performance.cache-size: 256MB
[root at gluster-test-1 ~]#

Then I mounted the volume with gluster client on another machine. I created
an 80Mbytes file called 80, and here you have the reading test:

[root at gluster-client-1 gluster_vol]# dd if=/mnt/gluster_vol/80 of=/dev/null
bs=1M
80+0 records in
80+0 records out
83886080 bytes (84 MB) copied, 1,34145 s, 62,5 MB/s
[root at gluster-client-1 gluster_vol]# dd if=/mnt/gluster_vol/80 of=/dev/null
bs=1M
80+0 records in
80+0 records out
83886080 bytes (84 MB) copied, 0,0246918 s, 3,4 GB/s
[root at gluster-client-1 gluster_vol]# dd if=/mnt/gluster_vol/80 of=/dev/null
bs=1M
80+0 records in
80+0 records out
83886080 bytes (84 MB) copied, 0,0195678 s, 4,3 GB/s
[root at gluster-client-1 gluster_vol]#

Cache is working flawlessly, (even though that 80 Mbytes is smaller than
the min-file-size value, but I don't care about it right now) what I don't
get is where cache is being stored. Is it stored on the client side or on
the server side? According to documentation, the io-cache translator could
be loaded on both sides (client and server), how can I know where it is
being loeaded? It looks like as it was being stored locally because of the
speed, but I'd like to be sure.

Thanks!

-- 
Pavlik Salles Juan José
Blog - http://viviendolared.blogspot.com
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